Thanks to the fine carpenters at the Academy, we now have our Sloan Digital Sky Survey (SDSS) plate mounted and hanging on my classroom wall. It has been encased in a wooden box filled with ornamental lights, giving it that astronomical view.
The plate has a bunch of markings on it to help astronomers with the data collection process. Fiber optic bundles are grouped together such than each bundle gets a section of the plate bounded by a black border. Blue circles around the openings correspond to the galaxies locations for which spectra are being collected. The black circles around the holes correspond to guide star locations in the field.
Information on the plate itself is rather interesting. This is a plate for the Baryon Oscillation Spectroscopic Survey (BOSS) which has the goal of mapping baryon acoustic oscillations signatures by looking at the spectra of some 1.5 million luminous red galaxies. The survey will help astronomers to place limits on the universe’s expansion rate, and more! The plate here was used to hold optical fibers on the SDSS telescope’s focal plane so that each fiber, attached to a hole on the plate, captures light from just one galaxy. That light is then funneled down the fiber optic path to a spectrograph.
- SDSS BOSS Plate 6192/56269
- Observed on MJD 56269 (8-December-2012)
- Plate center: RA = 7.98654794692993, dec = 16.3795967102051
The SDSS then converts all the spectra to plots and measures their z (redshift) values, among other things. One spectra from the many on this plate is below: